US Patent 10199502 Structure of S/D contact and method of making same

A semiconductor device includes a fin feature in a substrate, a stack of semiconductor layers over the fin feature. Each of the semiconductor layers does not contact each other. The device also includes a semiconductor oxide layer interposed between the fin feature and the stack of the semiconductor layers. A surface of the semiconductor oxide layer contacts the fin feature and an opposite surface of the semiconductor oxide layer contacts a bottom layer of the stack of semiconductor layers. The device also includes a conductive material layer encircling each of the semiconductor layers and filling in spaces between each of two semiconductor layers.